hexafluorobenzene Property

Melting point:

3.7-4.1 °C (lit.)

Boiling point:

80-82 °C (lit.)

Density 

1.612 g/mL at 25 °C (lit.)

refractive index 

n20/D 1.377(lit.)

Flash point:

50 °F

storage temp. 

Sealed in dry,Room Temperature

form 

Liquid

Specific Gravity

1.612

color 

Clear colorless to slightly yellow

Water Solubility 

Immiscible with water.

Merck 

14,4686

BRN 

1683438

Dielectric constant

2.0499999999999998

Stability:

Stable. Incompatible with strong oxidizing agents. May form complexes with transition metals which can explode when heated. Highly flammable.

CAS DataBase Reference

392-56-3(CAS DataBase Reference)

NIST Chemistry Reference

Benzene, hexafluoro-(392-56-3)

EPA Substance Registry System

Benzene, hexafluoro- (392-56-3)

Safety

Hazard Codes 

F,Xi

Risk Statements 

11-36/37/38

Safety Statements 

16-33-7/9-29-26-37/39

RIDADR 

UN 1993 3/PG 2

WGK Germany 

3

RTECS 

DA3050000

F 

10

Hazard Note 

Highly Flammable

TSCA 

Yes

HazardClass 

3

PackingGroup 

II

HS Code 

29039990

Toxicity

guinea pig,LCLo,inhalation,11800ppm/4H (11800ppm),BEHAVIORAL: ATAXIASENSE ORGANS AND SPECIAL SENSES: LACRIMATION: EYELUNGS, THORAX, OR RESPIRATION: OTHER CHANGES,National Technical Information Service. Vol. OTS0571186,

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Danger

Hazard statements

H225Highly Flammable liquid and vapour

Precautionary statements

P210Keep away from heat/sparks/open flames/hot surfaces. — No smoking.

P233Keep container tightly closed.

P240Ground/bond container and receiving equipment.

P241Use explosion-proof electrical/ventilating/lighting/…/equipment.

P242Use only non-sparking tools.

P243Take precautionary measures against static discharge.

hexafluorobenzene Chemical Properties,Usage,Production

Description

Hexafluorobenzene, HFB, C6F6, or perfluorobenzene is an organic, aromatic compound. In this derivative of benzene all hydrogen atoms have been replaced by fluorine atoms. The technical uses of the compound are limited, although it is recommended as a solvent in a number of photochemical reactions. In the laboratory hexafluorobenzene is used as standard in fluorine-19 NMR spectroscopy, solvent and standard in carbon-13 NMR, solvent in proton NMR, solvent when studying some parts in the infrared and solvent in ultraviolet–visible spectroscopy, as hexafluorobenzene itself hardly shows any absorbance in the UV region.

Chemical Properties

colourless liquid

Uses

Hexafluorobenzene is used as a solvent in photochemical reactions. It is also used as a reference compound in fluorine-19 NMR, carbon-13 NMR. It is used as a solvent in proton NMR, IR spectrum and UV-spectra. It is used as anticorrosive, antifriction and anti-tumor agents. Further, it is used as a reference molecule to investigate tissue oxygenation in vivo studies. It forms series of 1:1 complexes with naphthalene, anthracene, phenanthrene, pyrene and triphenylene.

Uses

Hexafluorobenzene can be used as a standard in ¹⁹Fluorine NMR (nuclear magnetic resonance) spectroscopy and also as a solvent in ¹³Carbon and ¹H NMR spectroscopy.

Definition

ChEBI: A member of the class of fluorobenzenes that is benzene in which all six hydrogen atom have been replaced by fluorine.

Application

Hexafluorobenzene can react with:
Ethyl magnesium bromide in the presence of transition metal halides to form the corresponding perfluoroarylmagnesium compound that can undergo Grignard reactions.
The sodium salt of the appropriate phenol in 1,3-dimethyl-2-imidazolidinone (DMEU) to form the corresponding hexakis(aryloxy)benzenes.
It can be used:
As a ligand to synthesize novel ruthenium(0) and osmium(0) hexafluorobenzene complexes.
As a solvent and promoter for the ring-closing metathesis (RCM) to form tetrasubstituted olefins in the presence of a ruthenium-based catalyst.

Reactions

For example, hexafluorobenzene adds chlorine quite readily under rather mild conditions to give hexachlorohexafluorocyclohexane. The catalytic reduction of hexafluorobenzene with hydrogen to penta. and tetra-fluorobenzene at 300 °C, using a platinum catalyst, probably proceeds by a free-radical mechanism. Although the addition of chlorine to hexafluorobenzene is an example of a free-radical addition reaction, the reduction of hexafluorobenzene with hydrogen is classified as a freeradical substitution reaction.
One of the earliest and, perhaps, most complicated reactions of hexafluorobenzene is one reported by Desirant. This interesting reaction, whic h is the only example of a high· temperature (above 300°C) reaction of hexafluorobenzene reported to date, involves the pyrolysis of the molecule in a platinum reactor at 850°C. Among the many products produced in this reaction , octafluorotoluene and decafluorobiphenyl were identified. This highly complex reaction probably could also be classified, in some respects, as a free-radical substitution reaction. There is also some less direct evidence that hightemperature reactions of hexafluorobe nzene do occur. In the synthesis of hexafluorobenzene by the pyrolysis of tribromofluoromethane, bromopentafluorobenzene is a signifi'cant by-product. Lesser amounts of higher brominated fluorocarbons are formed as well, along with copious quantities of bromine. This rather complex reaction is illustrated below.
CFBr3--630-640℃-->C6F6+Br2+C6F5Br+C6F4Br2+etc.

General Description

Hexafluorobenzene was repoted to be a sensitive ¹⁹F NMR indicator of tumor oxygenation. Rotational Raman spectra of hexafluorobenzenehas been studied under high resolution using a single mode argon laser as the exciting source. Hexafluorobenzene in the gas phase reacts spontaneously with lithium amalgam, to give a solid and intimate mixture of lithium fluoride and elemental polymeric carbon with a small amount of superstoichiometric lithium. Hexafluorobenzene forms series of 1:1 complexes with naphthalene, anthracene,phenanthrene, pyrene and triphenylene.

Hazard

Toxic by inhalation. Combustible.

Synthesis

The direct synthesis of hexafluorobenzene from benzene and fluorine is not possible. The synthetic route proceeds via the reaction of alkali-fluorides with halogenated benzene:
C6Cl6 + 6 KF → C6F6 + 6 KCl

Purification Methods

Main impurities are incompletely fluorinated benzenes. Purify it by standing in contact with oleum for 4hours at room temperature, repeating until the oleum does not become coloured. Wash it several times with water, then dry it with P2O5. Finally purify it by repeated fractional crystallisation. [Beilstein 5 III 523, 5 IV 640.]